Low birth weight piglets face significant welfare challenges and higher mortality risk. Understanding the relationship between birth weight, genetics, and management helps improve outcomes for the most vulnerable animals.
The welfare of underweight piglets begins in the womb with intrauterine crowding effects on development, continues with competitive disadvantage after birth, and may extend throughout their lives through lasting effects on brain development and stress responsiveness. This makes birth weight a welfare issue that cannot be fully addressed by post-birth management alone - breeding decisions that prioritize extreme prolificacy at the expense of piglet viability represent a systemic welfare compromise. Welfare-centered pig breeding would set minimum acceptable birth weight thresholds alongside litter size targets. For piglets already born underweight, intensive early intervention including ensuring colostrum access, providing supplemental warmth, and using nurse sow systems gives these animals the best chance of welfare-positive outcomes.